am

Print a list of AWS EC2 instances that match a name, and run commands remotely on those instances.

Prerequisites

1. aws-cli installed and your ~/.aws config setup
2. ssh access to the relevant instances you want to administrate

Installation

Get the script into your $PATH:

git clone git@github.com:alexlance/am
ln -s am/am /usr/bin/am

If you'd like tab-completion for your instance names:

# copy the tab-completion script into the proper place:
cp am.completion /etc/bash_completion.d/am

# add a once per hour cronjob
0 * * * * (for region in ${AWS_REGIONS:-$(aws configure get region)}; do aws --region $region ec2 describe-tags --filters "Name=resource-type,Values=instance" --query "join(' ',sort(Tags[?Key=='Name'].Value))" | tr -d '"'; done) > /tmp/.instances

These environment variables may be useful:

# a list of AWS regions to target
AWS_REGIONS="ap-southeast-2 us-west-2"

# to skip typing out your sudo password
AM_SUDO_PASSWORD="tops3cret"

# use `ssh -f` for faster command execution when there are many servers
AM_FAST=1

# sometimes you want to exactly match an instance name, instead of a star-pattern-star match
AM_EXACT=1

Usage

# usage:
am <instancename> [command]

# print a list of servers matching this name
am webservers

# run a command on a bunch of servers that match this name
am webservers 'ps -ef | grep apache'

# run a shell on each in turn - basically ssh-ing to the server
am webservers bash

# any mentions of sudo in the command will be replaced with 'echo "$password" | sudo -S'
# so you only need to type your sudo password once, even across multiple servers
am webservers 'sudo docker start $(sudo docker ps -qa -f Name=stuff)'

# use shell heredocs if you want to run a bunch of commands
am webservers <<EOF
sudo service apache stop
sudo rm -rf /var/log/apache/*
sudo service apache start
EOF

# use env var AM_FAST=1 to run commands using ssh -f, for backgrounded execution
# this speeds up command execution when targeting a lot of servers
AM_FAST=1 am pattern-that-matches-many-servers 'run a command, the output is going to be all jumbled up'

Tricks

# search for instances by name fuzzy match
am name-of-thing

# or by instance id
am i-0b0f3c0bea60e1d

# or by partial ip address
am 172.22

# or by partial instance type
am r4

# or by AMI id
am ami-abcd1234

# non-fuzzy exact name matches only
AM_EXACT=1 am exact-name-of-thing

# tab completion works (if you copy am.completion /etc/bash_completion.d/am)
am dashboard<tab>

# ssh to one or many boxes sequentially
am dashboard bash / am i-abdedfsd1234545 bash

# take a look at all docker processes (only need to type sudo password once, even though multiple machines)
am dashboard sudo docker ps

# run a command on a bunch of servers but without waiting for each command to finish (useful when lots of machines)
AM_FAST=1 am dashboard sudo apt-get install -y tmux

# if you need to run lots of commands, you can use single quotes or heredocs
am dashboard 'sudo docker restart $(sudo docker ps -q)'

# heredoc for lots of ad-hoc commands
am dashboard <<'EOF'
ids=$(sudo docker ps -qa)
sudo docker restart $ids
more commands go here
and here
and here
EOF

# easily sort the results by any column
am dashboard | sort -k8

# easily parse out a particular field from the results, eg grab only the instance-ids
am dashboard | awk '{print $2}'

# then whack them in a loop if you like
for i in $(am dashboard | awk '{print $2}'); do aws ec2 terminate-instances --instance-ids $i; done

# interactive
function bam() {
  ops="$(am $1 | nl -n ln | tee /dev/stderr)"
  read -p "Enter server number: " number
  id=$(echo "$ops" | awk '{print $3}' | sed "${number}q;d")
  am $id bash
}